Members of NanOp

MAX-BORN-INSTITUT für Nichtlineare Optik und Kurzzeitspektroskopie, Berlin Dr. A. Bärwolf, Dr. J.W. Tomm

The MBI focuses on research in the field of nonlinear optics and short pulse spectroscopy, however, there is also a long-term tradition in the field of applied research on diode lasers. During the last years intense research activities in the field of optical and thermal properties of high-power laser diode arrays have been established. Main topic is the investigation of non-invasive optical analytical methods for characterizing laser diodes:

Experimental as well as modeling work on thermal properties has been performed: The Micro-Raman technique has been further developed for analyzing facet temperatures in operating quantum well (QW) devices. The ultra-large depth resolution of this technique (better than 100 nm) as well as remarkable lateral resolution (about 1 µm) qualifies this technique as an appropriate tool for the investigation of nanodevices. Model calculations allow conclusions from the experimentally obtained facet temperatures with respect to the thermal balance of the device.

Gradual aging processes in QW devices: These processes can be very successfully investigated by the use of various kinds of photoelectric spectroscopy. Localization and Identification of defects (defect levels) as well as comparative measurements with other techniques were realized.

Strain measurement in QW structures. Selective spectroscopy of the confined transitions in QWs of devices allows the separation of effects due to quantum confinement and strain also under different operation condition of the diodes.
The application of these methods to nano-devices and the know-how on high-power QW devices will be a useful contribution of our group to NanOp.